Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Silver Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,567 records · Page 87Linked to original sources
PubMed2006

Self-assembly of a bis-porphyrinic supramolecular rectangle using two orthogonal binding strategies.

A bis-porphyrinic rectangle is created via a double self-assembly algorithm using two orthogonal coordination themes, i.e. first a 90 degrees building block composed of a dynamic heteroleptic Cu(I) or Ag(I) bisphenanthroline followed by a coordinative dimerization using the pyridine-zinc porphyrin motif; the spectroscopic and electrochemical properties as well as the dynamic nature of the supramolecule were tested.

Algorithms↗
PubMed1956

Observations on the basement membranes in rat kidney.

Basement membranes in the kidney are made up of a homogeneous matrix. In argyria, silver passes from the blood in the ionic form and diffuses into the kidney basement membranes in which it is precipitated. X-ray diffraction studies of "silver-stained" rat kidneys show that most of the silver in the kidneys is combined with some form of sulfur. Histochemical staining for sulfhydryls and disulfides demonstrates the presence of these groups in basement membranes. It appears that silver ions combine with either or both the sulfhydryl or disulfide groups in the basement membranes and also in mitochondria (when the silver diffuses into a cell).

Animals↗
PubMed2005

Modelling of composite neutron scintillators.

Composite neutron scintillators consisting of neutron-insensitive fluorescent dopant particles (e.g. ZnS:Ag) embedded in a matrix material containing isotopes with high neutron cross sections that emit energetic charged particles (e.g. 6Li) are a popular method for neutron detection in a variety of applications. The size and volume doping fraction of the fluorescent dopant particles and the densities of both dopant particles and the matrix material determine the characteristics of the pulse-height spectrum of emitted light and the probability that capture of a neutron will result in scintillation. In this work, we characterise the effects of these parameters for ZnS:Ag particles in a lithiated glass matrix using a Monte Carlo simulation of composite neutron detectors that we have constructed.

Computer Simulation↗
PubMed1975

Suppression of leukocyte chemotaxis in vitro by chemotherapeutic agents used in the management of thermal injuries.

Polymorphonuclear leukocytes from burned patients exhibit suppressed chemotaxis possibly related to the susceptibility of such patients to opportunistic infection. This study assesses the effect of normal serum upon burn-suppressed leukocytes and the effects of three commonly used topical chemotherapeutic agents upon the chemotaxis exhibited by granulocytes from normal controls. In vitro incubation with normal serum restored chemotaxis to normal in the suppressed granulocytes from burned patients. The serum factor responsible for this restoration was heat labile. Serum albumin alone did not exhibit this effect. Both mafenide and silver sulfadiazine suppressed the chemotactic function of granulocytes obtained from normal controls, while silver nitrate exhibited no such activity. Studies of the chemotactic function of control granulocytes after incubation with sera from burned patients yielded similar results; only the sera from patients treated with silver nitrate failed to suppress normal leukotaxis. The chemotactic impairment found in leukocytes from burned patients, however, while related to burn size and predictive of prognosis, did not vary with the agent used for the topical therapy. These data suggest the presence of a reversible intrinsic defect in leukotaxis consequent to burn injury, related to some factor deficient in burn serum. In addition, extrinsic impairment of normal granulocyte leukotaxis by two commonly used chemotherapeutic agents is demonstrated.

Administration, Topical↗
PubMed1997

Surface characterization of amalgam made with Hg-In liquid alloy.

When amalgam was triturated with Hg-In liquid alloys instead of pure mercury, the resultant amalgams released a significantly smaller amount of mercury vapor during setting. To understand the mechanisms responsible for the drastic decrease in mercury evaporation from the In-containing amalgam, we used Auger Electron Spectroscopy to examine surface oxide films on amalgams made with Hg-10 wt% In or pure mercury. The surface of the In-containing amalgam was rapidly covered with both indium and tin oxide films. Greater amounts of oxygen were found on the gamma 1 Ag-Hg matrix in the In-containing amalgam than in the amalgam without indium. The rapid formation of the oxide film contributes to a reduction in the mercury release from the In-containing amalgam by forming an effective barrier to evaporation.

Copper↗
PubMed1982

Silver staining of the nucleolus organizer regions (NOR) requires clusters of sulfhydryl groups.

Silver stainability of nucleolus organizer regions (NORs) appears to be correlated with the presence of grouped sulfhydryl (SH) side chains of proteins. In fact, heavy metals with high affinity for SH groups, such as Hg and Cu, do prevent the silver staining reaction. Ferricyanide, which is known to oxidize SH to disulfides, also prevents any further reaction with silver. On the other hand, alkali and reducing agents (mercaptoethanol, cyanide) do not affect silver stainability of the NORs. These results show that the silver staining reaction is not related to disulfide or persulfide groups and that alkali-soluble, acidic nuclear proteins per se do not play a major role in this process.

Cell Nucleolus↗
PubMed1985

Immunoelectron microscopic labeling of immunoglobulin in plasma cells after osmium fixation and epoxy embedding.

Previous studies have found that immunoglobulin cannot be immunolabeled in tissues prepared for electron microscopy by usual methods. To test this conclusion, we used a protein A-gold postembedding immunolabeling method on tissues that were fixed in glutaraldehyde, post-fixed in osmium tetroxide, and embedded in epoxy resin; sections were pretreated with sodium metaperiodate. A variety of common fixation protocols were also used and the most suitable conditions for immunolabeling were determined. This technique permitted the ultrastructural localization of immunoglobulin light chains in optimally preserved and contrasted plasma cells from human tonsil, lymph nodes, plasmacytomas, and a renal biopsy. We were able to demonstrate multiple antigens in the same tissue and label antigens in tissues that had been stored for many years in epoxy resin. The technique allows quantitation of the gold label over plasma cell organelles and therefore gives information about the immunoglobulin secretory pathway in these cells. We found that the protein A-gold procedure compares favorably in technical ease with the immunoperoxidase, avidin-biotin peroxidase, and immunoglobulin-colloidal gold immunolabeling methods, and has added advantages in allowing precise localization and quantitation of the labeled antigen.

Epoxy Compounds↗
PubMed2006

Resonance Raman evidence of immobilization of laccase on self-assembled monolayers of thiols on Ag and Au surfaces.

Resonance Raman (RR) and surface-enhanced Raman scattering (SERS) spectroscopy have been used to study immobilization of laccase on self-assembled monolayers (SAMs) of thiols containing carboxylic and amino groups, deposited on silver and gold electrodes. A new, indirect way of monitoring laccase bound to the thiol-coated Ag and Au surfaces is presented. It was demonstrated that by recording the resonance Raman spectra of the colored product of the oxidation of syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehydeazine) by laccase in the presence of molecular oxygen, one may easily confirm binding as well as enzymatic activity of laccase immobilized on the SAMs modified silver and gold surfaces.

3-Mercaptopropionic Acid↗
PubMed2006

Micromethods for the characterization of lipid A-core and O-antigen lipopolysaccharide.

Methods for rapid and simple analysis of lipopolysaccharide (LPS) from bacterial whole-cell lysates or membrane preparations have contributed to advancing our knowledge of the genetics of the LPS biogenesis. LPS, a major constituent of the outer membranes in Gram-negative bacteria, has a complex mechanism of synthesis and assembly that requires the coordinated participation of many genes and gene products. This chapter describes a collection of methods routinely used in our laboratory for the characterization of LPS in Escherichia coli and other bacteria.

Bacteriological Techniques↗
PubMedDate not supplied

Isolation of two cytotoxic diterpenes from the fern Pteris multifida.

From aerial parts of the fern Pteris multifida Poir. (Polypodiaceae) two diterpenes, entkaurane-2 beta, 16 alpha-diol and ent-kaur-16-ene-2 beta, 15 alpha-diol, were isolated by repeated column chromatography using silica gel and silica gel impregnated with silver nitrate. The structures were confirmed by spectroscopic methods. Both compounds showed a moderate cytotoxicity to Ehrlich ascites tumour cells.

Animals↗
PubMed1990

Cytochemical detection of disulfide and sulfhydryl groups in lamprey aortic microfibrils.

A cytochemical study was performed on the lamprey ventral aorta with special reference to disulfide and sulfhydryl groups of microfibrils, using the high-iron diamine-thiocarbohydrazide-silver proteinate (HID-TCH-SP) method combined with several other types of treatment. The HID-TCH-SP staining observed was classified into three categories: 1) weak staining in the periphery of collagen fibrils, 2) moderate staining in the boundaries of collagen fibrils, microfibrils and smooth muscle cells, and 3) intense staining of microfibrils. The first and second categories of staining were considered to represent chondroitin and/or heparan sulfate because of sensitivity of the staining to chondroitinase ABC (ChABC) and its specific localization. By contrast, the third category of staining was considered to represent disulfide and sulfhydryl groups of microfibrillar glycoprotein, because it was disclosed only after Oxone oxidation or thiosulfation and was not removed by ChABC digestion. Although this staining reactivity was not apparently altered by SH blockade prior to oxidation or thiosulfation, it was markedly diminished or completely inhibited by S-S reduction followed by SH blockade. These results indicate that lamprey aortic microfibrils contain more S-S groups than SH groups.

Actin Cytoskeleton↗
PubMed2002

Purification and characterization of beta-N-acetylhexosaminidase from rice seeds.

N-Acetyl-beta-D-hexosaminidase (beta-HexNAc'ase) (EC 3.2.1.52) was purified from rice seeds (Oryza sativa L. var. Dongjin) using ammonium sulfate (80%) precipitation, Sephadex G-150, CM-Sephadex, and DEAE-Sephadex chromatography, sequentially. The activities were separated into 7 fractions (Fsub1;- F7sub7) by CM-Sephadex chromatography. Among them, F6 was further purified to homogeneity with a 13.0% yield and 123.3 purification-fold. The molecular mass was estimated to be about 52 kDa on SDS-PAGE and 37.4 kDa on Sephacryl S- 300 gel filtration. The enzyme catalyzed the hydrolysis of both p-nitrophenyl-N-acetyl-beta-D-glucosaminide (pNP-GlcNAc) and p-nitrophenyl-N-acetyl-beta-D-galactosaminide (pNPGalNAc) as substrates, which are typical properties of beta-HexNAc'ase. The ratio of the pNP-GlcNAc'ase activity to the pNP-GalNAc'ase activity was 4.0. However, it could not hydrolyze chitin, chitosan, pNP-beta-glucopyranoside, or pNP-beta-galactopyranoside. The enzyme showed K(M), V(max) and K(cat) for pNP-GlcNAc of 1.65mM, 79.49mM min(1), and 4.79 x 10(6) min(1), respectively. The comparison of kinetic values for pNPGlcNAc and pNP-GalNAc revealed that the two enzyme activities are associated with a single binding site. The purified enzyme exhibited optimum pH and temperature for pNPGlcNAc of 5.0 and 50 degrees C, respectively. The enzyme activity for pNP-GlcNAc was stable at pH 5.0-5.5 and 20-40 degrees C. The enzyme activity was completely inhibited at a concentration of 0.1 mM HgCl(2) and AgNO(3), suggesting that the intact thiol group is essential for activity. Chloramine T completely inhibited the activity, indicating the possible involvement of methionines in the mechanism of the enzyme.

Acetylgalactosamine↗
PubMed1992

Enhanced expression of glial fibrillary acidic protein and the cupric silver degeneration reaction can be used as sensitive and early indicators of neurotoxicity.

The mammalian central nervous system is composed of a large and diverse array of its two principle cell types, neurons and glia. Given this extreme cellular heterogeneity, it is not surprising that targets of neurotoxic insult often are diverse and unpredictable. In devising strategies to assess neurotoxicity, one must overcome the obstacle posed by not knowing where to look for damage. Our approach to the detection and localization of sites of toxicant-induced damage has been to take advantage of two general responses to nervous system insult, astrogliosis and argyrophilia. Assays for GFAP, the principle intermediate filament protein of astrocytes, have been devised to quantify astrogliosis and a modified cupric silver degeneration stain has been employed to examine patterns of argyrophilia. Using these methods, we found that increases in GFAP and the occurrence of argyrophilia are consistent responses to neurotoxic insults. Moreover, increments in these two indicators reveal dose-, time- and region-dependent patterns of neurotoxicity at toxicant dosages below those that cause light microscopic evidence of cell loss or damage. The rapid onset of astrogliosis and argyrophilia following specific toxicant exposures suggests that the signals underlying these events are among the earliest that can be linked to the neurotoxic state.

Animals↗